Before going towards directly to real time senario of trigger lets go through basics of trigger
Trigger
Trigger is piece of code that is executes before and after a record is Inserted / Updated / Deleted from the force.com database
Trigger Context Variables:
- IsInsert:- Returns true if the trigger was fired due to insert operation.
- IsUpdate:- Returns true if the trigger was fired due to update operation.
- IsDelete:- Returns true if the trigger was fired due to delete operation.
- IsBefore:- Returns true if the trigger was fired before record is saved.
- IsAfter:- Returns true if the trigger was fired after record is saved.
- New:- Returns a list of new version of sObject records:.
- Old:- Returns a list of old version of sObject records.
- NewMap:- Returns a map of new version of sObject records. (map is stored in the form of map
- OldMap:- Returns a map of old version of sObject records. (map is stored in the form of map
- Size:- Returns a list of new version of sObject records:.
- isExecuting:- Returns true if the current apex code is a trigger.
Scenarios
- create a trigger on account object which will prevent the users in creating duplicate account based on the name
- Create trigger Whenever an Account Name is modified send an email notification to the contact of an account.
- Create trigger on event object to avoid sessions overlap .
- Write trigger to throw error when account is inserted with IsActive(Checkbox) field is True It should always FALSE
-
2 objects Account and Dsignation parent object: Account Child object: Designation Relationship: Lookup(Field name Account__c on Designation object) If an Account has Designation with Title CEO(Field name Title__c) then the Account field "Area__c" cannot be blank.
- trigger on contentversion object which inserts contentdocumentlink to share files specific user whenever a new file is uploaded.
- Trigger on contentversion object which inserts contentdocumentlink to share files specific user whenever a new file is uploaded.
- Write a trigger automatically create the Pricebook entry for each Product record inserted.
Code
trigger AccountDuplicateTrigger on Account (before insert,before update) {
list accountNames=new list();
for(Account accountVar:trigger.new)
{
accountNames.add(accountVar.name);
}
list listOfDuplicateAccounts=[select id,name from Account where name in :accountNames];
for(Account account:trigger.new)
{
if(trigger.isInsert){
if(listOfDuplicateAccounts.size()!=0)
{
account.addError('Account already exists with this name');
}
}
if(trigger.isUpdate)
{
for(Account oldaccount :trigger.old)
{
if(account.Name!=oldAccount.Name && listOfDuplicateAccounts.size()!=0)
{
account.addError('Account already exists with this name');
}
}
}
}
}
Code
trigger AccountDuplicateTrigger on Account (before insert,before update) {
list accountNames=new list();
for(Account accountVar:trigger.new)
{
accountNames.add(accountVar.name);
}
list listOfDuplicateAccounts=[select id,name from Account where name in :accountNames];
for(Account account:trigger.new)
{
if(trigger.isInsert){
if(listOfDuplicateAccounts.size()!=0)
{
account.addError('Account already exists with this name');
}
}
if(trigger.isUpdate)
{
for(Account oldaccount :trigger.old)
{
if(account.Name!=oldAccount.Name && listOfDuplicateAccounts.size()!=0)
{
account.addError('Account already exists with this name');
}
}
}
}
}
Code
trigger validateoverlap on Session__c(before insert)
{
Set eventID = set();
for(Session__c sNew : trigger.new)
{
//Eent Reference field
eventID.add(sNew.Event__c);
}
List ExistingSessionList = [Select StartDate__c , EndDate__c from Session__c where event__c in : eventID];
for(Session__c sNew : trigger.new)
{
for(Session__c sOld : ExistingSessionList)
{
if(sNew.StartDate__c >= sOld.StartDate__c && sNew.StartDate__c <= sOld.EndDate__c)
{
sNew.addError('Overlap Session');
}
}
}
}
TRIGGER
trigger AccountTriggerToCheckValidation on Account (before insert) {
if(trigger.IsInsert && trigger.IsBefore) {
AccountTriggerToCheckValidation_handler.checkIsActiveField(trigger.new);
}
}
CLASS HANDLER
public class AccountTriggerToCheckValidation_handler {
public static void checkIsActiveField(List accList) {
try{
if(accList.size() > 0) {
for (Account ac : accList) {
if (ac.IsActive__c == true) {
ac.addError('This Account cannot be created with IsActive = true.');
}
}
}
} catch(Exception e) {
System.debug('The following exception has occurred: ' + e.getMessage());
System.debug('The following Line : ' + e.getLineNumber());
}
}
}
TRIGGER
trigger demo on Account (after update) {
if(trigger.isAfter && trigger.isUpdate ){
system.debug('hello buddy');
demohandler.validationdemo(trigger.old);
}
}
CLASS HANDLER
public class demohandler {
public static void validationdemo(List acc){
Set idSet = new Set();
for(Account acc1: acc){
idSet.add(acc1.id);
}
List accList = [Select id, Area__c,(select id, Title__c from Designations__r) from Account where Id IN: idSet];
for(Account act:Designation__c.){
for(Designation__c deg:accList.act){
if(deg.Title__c == 'CEO' && act.Area__c == ''){
act.addError('Area should not be blank');
}
}
}
}
}
Code
eed to put a check to verify if ContentDocumentLink records exist before putting it into final list ContentDocumentList. Logic will be like this.
trigger ContentVersionTrigger on ContentVersion (after insert) {
if(!TriggerRunOnce.hasAlreadyfired())
{
List users = [select user.id, user.Email, user.FirstName, user.LastName, user.profile.name, user.Username, user.IsActive
FROM user, user.profile
where user.LastName IN ('***','***') and user.IsActive=true];
Set contentDocumentIdSet = new Set();
for(ContentVersion cv:trigger.new)
{
if(cv.ContentDocumentId != null)
{
contentDocumentIdSet.add(cv.ContentDocumentId);
}
}
List lstContentDocumentlink = [SELECT ContentDocumentId, LINKEDENTITYID
FROM ContentDocumentLink WHERE ContentDocumentId IN:contentDocumentIdSet];
List ContentDocumentList = new List();
for(ContentVersion cv:trigger.new)
{
system.debug('at 5 '+cv);
if(cv.ContentDocumentId != null && !lstContentDocumentlink.contains(cv.ContentDocumentId))
{
for(user u:users){
if(u.Id != cv.OwnerId){
ContentDocumentLink cdl = new ContentDocumentLink(ContentDocumentId=cv.ContentDocumentId,LINKEDENTITYID = u.Id,SHARETYPE='C');
ContentDocumentList.add(cdl);
}
}
}
}
insert ContentDocumentList;
TriggerRunOnce.setAlreadyfired();
}
}
Code
trigger ContentVersionTrigger on ContentVersion (after insert) {
if(!TriggerRunOnce.hasAlreadyfired())
{
List users = [select user.id, user.Email, user.FirstName, user.LastName, user.profile.name, user.Username, user.IsActive
FROM user, user.profile
where user.LastName IN ('***','***') and user.IsActive=true];
Set contentDocumentIdSet = new Set();
for(ContentVersion cv:trigger.new)
{
if(cv.ContentDocumentId != null)
{
contentDocumentIdSet.add(cv.ContentDocumentId);
}
}
List lstContentDocumentlink = [SELECT ContentDocumentId, LINKEDENTITYID
FROM ContentDocumentLink WHERE ContentDocumentId IN:contentDocumentIdSet];
List ContentDocumentList = new List();
for(ContentVersion cv:trigger.new)
{
system.debug('at 5 '+cv);
if(cv.ContentDocumentId != null && !lstContentDocumentlink.contains(cv.ContentDocumentId))
{
for(user u:users){
if(u.Id != cv.OwnerId){
ContentDocumentLink cdl = new ContentDocumentLink(ContentDocumentId=cv.ContentDocumentId,LINKEDENTITYID = u.Id,SHARETYPE='C');
ContentDocumentList.add(cdl);
}
}
}
}
insert ContentDocumentList;
TriggerRunOnce.setAlreadyfired();
}
}
Code
trigger createPriceBookEntry on Product2 (after insert) {
List priceBookEntryList= new List();
String pricebkId= [SELECT id from Pricebook2 where isStandard=true][0].Id;
for(Product2 prod: trigger.new){
priceBookEntry priceBkEntry= new priceBookEntry();
priceBkEntry.Product2Id= prod.Id;
priceBkEntry.Pricebook2Id= pricebkId;
priceBkEntry.IsActive= True;
priceBkEntry.UnitPrice= 100; // Dummy Value
priceBkEntry.UseStandardPrice= False;
//Add more fields as per requirement
priceBookEntryList.add(priceBkEntry);
}
if(priceBookEntryList.size()>0){
insert priceBookEntryList;
}
}
